Devices for cutting off successive lengths of a continuously moving elongate workpiece such as tubing being formed in a tube mill are well known in the art. Typically, the tube cut-off apparatus consists of a die set mounted on a rail for selective movement along the length of the tubing. The upper die shoe of the die set is suitably mounted on a rail attached to an orbiting type ram operating in synchronism with the movement of the tubing being formed. The typical apparatus includes a first stage in the cutting which is accomplished by a prepiercing mechanism which includes a piercing blade which is reciprocated across the upper periphery of the tubing after the tubing is suitably clamped within the die set clamping jaws and just prior to the descent of the main cut-off blade. Prepiercing the tubing eliminates dimpling of the tubing.
A special problem is presented when the tube mill is producing tubing of a rectangular or square cross-section. In such instances it is necessary for the main cutter to approach tubing at a forty-five degree angle in respect of the horizontal and to pierce the square tube at the corner where two of the flat sides merge. In this fashion, dimpling of the tube is prevented.
A separate die set apparatus is required for the production of differing sized tubing and tubing formed from stock of differing gauge metal.
Since the die set apparatus is extremely heavy and rather difficult to remove and replace when disposed at an angle to the horizontal, the present invention was conceived.
It is an object of the invention to produce an apparatus which will facilitate the removal and replacement of the die set assemblies from one production run to another production run of tubing of a different size, shape, or wall thickness, for example.